An antenna mast for a wireless communication system is provided with one or more antennas at its upper end. The antennas may be of one type only or of different types and may be adapted to perform different functions in the wireless communication system. An example of such a function may be communication between a mobile communication device and a radio base station arranged in or at an antenna mast. Antennas performing this function are sometimes called sector antennas. A different example is communication between a radio base station in or at a relevant antenna mast and a radio base station at a different location than the relevant antenna mast.
Antenna masts may be constructed using different techniques. Examples are: steel lattice masts, masts comprising one or more steel tubes and masts comprising one or more reinforced concrete tubes. Accordingly, the expression “antenna mast” is intended to encompass antenna masts with an open structure, such a lattice, as well as masts with a closed structure such as a tubular mast, in the form of a tower.
The antennas at the top end of an antenna mast may be arranged so as to be fully visible or enclosed in a so-called radome. A radome may conceal the antennas from public view and accordingly prevent theft and damage of the antennas. A radome may also protect the antennas against influences of weather to a certain extent. A radome may be made from a glass fibre reinforced material.
Antennas of wireless communication systems may also be arranged on other buildings than dedicated masts. They may for instance be arranged on roof tops of office buildings or residential blocks. Also when arranged on a roof top, the antennas may be attached to a structure, e.g. a steel lattice construction.
DE 20 2005 010 140 U1 discloses an antenna construction wherein the antennas at the top of the construction are arranged inside an outer shell made from a material permeable to radio waves in the range of the antennas. According to one embodiment the antennas are attached to a pipe arranged centrally inside the outer shell.
DE 9407220 U1 and FR 2850418 disclose telecommunication antenna masts provided with several platforms for carrying antennas at their upper ends.
The positions of antennas of wireless communications systems must be able to be adjusted. In particular the sector antennas, each of which is arranged to cover a sector around e.g. an antenna mast or a module carrying antennas, often need to be adjusted in more than one direction. An antenna must be positioned and secured at least when installed for the first time to an antenna mast or in a module carrying antennas.